Vibration and MPG question

[green03]

i run whatever pressure it takes to have an even contact patch to the road.... look at your "road marks" on the tires. If it looks like the edges of the tires aren't contacting the road much use less air. if the edges (side of edges) of the tread look like they are being scuffed then you need more air. you will see a different pressure needed between the front and rear tires....

Matt R

 

[Randy_the_Hack]

Originally posted by chuck s
Passenger car tires have more capacity than needed to ensure a smooth, comfortable ride. Running 44psi is not necessary, makes the contact patch smaller due to a concave profile, and the ride harsh. 44psi is the maximum cold tire pressure. The tires are capable of handling higher pressures, so inflating to 44 (while a waste of time) isn't dangerous.

Aah... but herein lies the rub. By decreasing the contact patch, you decrease rolling resistance. By decreasing rolling resistance, you increase vehicle efficiency, i.e. fuel economy. The balancing effort is trying to keep the vehicle stable and the ride bearable yet keeping the rolling resistance as low as possible, otherwise you'll burn more fuel than you need to. You can have a very smooth and supple ride at 25 psi, and you can have a huge contact patch at 12-15 psi (recommended on the Outer Banks while driving on the sand dunes), but you're gonna get horrible handling and detestible mileage with underinflated tires.

Kind of a Ying & Yang thing...

Randy

 

[Remo]

Good point, Randy...

 

[green03]

Originally posted by Randy_the_Hack
Aah... but herein lies the rub. By decreasing the contact patch, you decrease rolling resistance. By decreasing rolling resistance, you increase vehicle efficiency, i.e. fuel economy. The balancing effort is trying to keep the vehicle stable and the ride bearable yet keeping the rolling resistance as low as possible, otherwise you'll burn more fuel than you need to. You can have a very smooth and supple ride at 25 psi, and you can have a huge contact patch at 12-15 psi (recommended on the Outer Banks while driving on the sand dunes), but you're gonna get horrible handling and detestible mileage with underinflated tires.

Kind of a Ying & Yang thing...

Randy

Yeah, but the center of your tires wear faster with over inflation possibly really cutting the life out of the treadwear.....

Again, kind of the half dozen and 6 in the other...

Matt R